Why do bugs like light

Before discussing why insects are attracted towards light, it needs to be clarified that all insects are not attracted towards light and based on that aspect alone, they can be divided into two groups — insects that have positive phototaxis and insects that have negative phototaxis. A moth is a positively phototactic bug that likes to follow the light source, while a cockroach is a negatively phototactic bug that mostly hides from light sources.

There are many theories regarding why insects are attracted towards light during the night, and one of them states that the positively phototactic bugs consider a light-source to be a safe haven for them. When they feel threatened due to one reason or the other, they fly upward, towards the nearby light source, which is usually at a higher place than where they are at the moment. Getting to a high and well lit point translates as better safety to them than going down into the dark.

Another popular theory states that bugs, do not exactly “like” light, but use it as a way to navigate themselves. Moths especially, are believed to be able to use natural sources of light that is the sun and the moon to understand which way they are heading. The problem begins when the source of light is manmade, thus the confusion. Both the sun and the moon remain high above and out of their reach, but when the insect is confused by the artificial street light, and then it is often found to circle the light in futile attempts to progress while keeping the light source at one side of its moving body.

Although there are multiple theories regarding why bugs are attracted by light, the exact reason is still not clear or proven beyond doubt. However, this tendency of the insects to fly towards the light is used by predators like lizards and spiders to their advantage. We often find a spider’s webbing towards a light source and preying lizards are a common sight at any brightly lit area that attract a lot of bugs.